Rolling Straightening Rollers for Single-Pass Pipe Diameter Reduction

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Solution Overview

Problem

Conventional methods for outer-diameter reduction and straightening of pipes or tubes require separate devices, leading to high costs and inefficiencies due to uneven strain distribution and friction issues, resulting in bending and compromised dimensional accuracy.

Innovation Solution

A rolling straightening machine with a design that integrates outer-diameter-reducing and straightening rolling in a single apparatus, featuring rollers with symmetrical and asymmetrical profiles to maintain uniform diameter reduction and correct bending, allowing for continuous processing without additional equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If outer-diameter-reducing rolling and straightening rolling are performed using different devices, then each process can be optimized independently, but apparatus cost, operation cost, and processing time increase significantly

Engineering Contradiction:
Improvedimensional accuracyVSAvoidnumber of rolling mills
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines outer-diameter-reducing rolling and straightening rolling into a single rolling mill device. The rolling mill includes a roller with an outer-diameter-reducing rolling portion and a straightening rolling portion integrated on the same roller surface, allowing both processes to be performed simultaneously in one apparatus, thereby reducing device complexity and cost while maintaining manufacturing precision

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rolling mill is designed to perform multiple functions - both outer-diameter reduction and straightening - using a single device. The roller surface is configured with different portions that can perform different rolling operations, making the device universal and eliminating the need for separate specialized equipment for each process

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If conventional separate rolling mills are used, then each process can be performed with dedicated equipment, but processing time and production efficiency decrease

Engineering Contradiction:
Improveprocessing speedVSAvoidtotal processing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent enables continuous processing by integrating both outer-diameter-reducing rolling and straightening rolling in a single pass through one rolling mill. The material undergoes both operations simultaneously without interruption or transfer between devices, eliminating idle time and achieving continuous useful action that improves productivity

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

By merging the two rolling processes into one device, the patent eliminates the time required for material transfer, setup changes, and sequential processing that would occur with separate rolling mills, thereby significantly reducing total processing time while maintaining high processing speed

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If inclined rolling mill is used for outer-diameter reduction, then some diameter reduction is achieved, but uniform strain distribution is difficult due to friction differences and material variations

Engineering Contradiction:
Improveouter diameter accuracyVSAvoidstrain distribution uniformity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The roller surface is designed with different local qualities - the outer-diameter-reducing rolling portion and the straightening rolling portion have different surface characteristics and geometries optimized for their specific functions. This local differentiation allows each portion to address specific strain distribution issues in its designated area, improving overall uniformity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs asymmetrical roller surface design where the straightening rolling portion has an asymmetrical shape with respect to the pass line, specifically designed to counteract the asymmetrical strain distribution caused by friction variations and material imperfections during outer-diameter reduction, thereby restoring uniformity

Inventive Principle:
Principle #4Asymmetry

4Stability of the object's composition

If asymmetrical straightening rolling is applied, then bending can be corrected, but the pass line must bend which may affect outer diameter uniformity

Engineering Contradiction:
ImprovestraightnessVSAvoidouter diameter uniformity
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The roller surface is segmented into distinct functional portions - the outer-diameter-reducing rolling portion and the straightening rolling portion. This segmentation allows each portion to perform its specific function independently, with the straightening portion applying asymmetrical rolling only in the region where bending correction is needed without affecting the previously achieved outer diameter uniformity

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables high-speed, high-accuracy outer-diameter reduction and straightening in a single apparatus, reducing production costs and time by uniformly distributing strain and maintaining dimensional accuracy.

Implementation Method 1

when a pipe or tube material or a bar material is subjected to outer-diameter-reducing rolling or the like to apply plastic strain

Methodology Applied
Scientific EffectPlastic strain: Plasticity

Implementation Method 2

the non-uniform lubricating condition between the pipe or tube material or the bar material and a tool or the like during working

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3960316B1Rolling-straightening machine and method for manufacturing pipe or bar using rolling-straightening machine
Publication Date: 2023.03.01 JFE STEEL CORP
  • EP3960316B1 patent drawingFigure 1
  • EP3960316B1 patent drawingFigure 2A~2B
  • EP3960316B1 patent drawingFigure 2C

AI summary

Provided is a rolling straightening machine which enables outer-diameter-reducing rolling and straightening rolling of a pipe or tube material or a bar material at high speed with high accuracy. The rolling straightening machine includes at least two rollers arranged across a pass line of a pipe or tube material or a bar material, the at least two rollers having a gap therebetween, the gap being defined by an outer-diameter-reducing rolling portion having a diameter reduced from an upstream side toward a downstream side in the rolling straightening machine and a straightening rolling portion continuous from an exit side of the outer-diameter-reducing rolling portion toward a downstream side of the rolling straightening machine, the rollers having shapes which are symmetrical about the pass line in the outer-diameter-reducing rolling portion, and in the straightening rolling portion, asymmetrical to the pass line in the outer-diameter-reducing rolling portion.